Portland State Aerospace Society (PSAS) | Similar organizations | Forum

Hi!

No one at PSAS can seem to remember seeing an email, but no matter, because we found you!

My name is Nathan Bergey and I have been working with PSAS for about 2 years. I will bring it up formally to the group at our next meeting (tomorrow—we meet actively, every Tuesday) but I think we would like to be friends! We are dedicated to open source and as excited as anyone else about amateur/private space flight.

Some more background on PSAS:

PSAS was started in 1998 by some Portland State University students who wanted to work with something more likely to explode than the normal, boring, labs. Several years later they had a whole group that was building amateur rockets and putting custom boards with microcontrollers on them and launching them. We soon discovered that to do real Guidance Navigation and Control (GNC) that we needed more fire power.

In 2005 we had completed a small rocket – 'LV2b' – that had a power-pc computer on board running a real-time linux kernel and some custom flight software. We had also had a custom IMU and a GPS board (more about that in a bit) in addition to temperature pressure sensors. We also added a small camera. The really, really cool thing about the flight was that we sent all the data down to the ground via a laptop wifi (802.11) card on channel one (which overlaps with an amateur radio band in the US) that was amplified and sent out on a patch antenna of our own design. We also transmitted the TV camera feed live on another band. The flight (up, over 5000 m) was very successful. We only lost something ~2 telemetry packets over the whole flight! But, unfortunately, it seems we had bad powder in our recovery system. The flight computer detected apogee, and we could see, from the telemetry feed, it desperately trying to fire the drogue chutes, and we even fired the manual override (via a direct DTMF link) but nothing ever happened and all 50 lbs of rocket came straight down into the ground. In fact since we still had the telemetry link we know that it was going over 500 mph at impact. Needless to say we didn't recover anything useful.

We believe that it did prove our techniques (minus recovery) because the rocket was nearly 100% custom. And all using commercial off the shelf (COTS) parts. And it flew very nicely. We also have position data for every 0.001 second of the flight :)

In the time since then we have been getting our feet back under ourselves. We now have 'LV2c' and we took the break as a chance to modernize the flight computer. We also have a new and improved recovery system, which we tested a over and over again, including fireing it in a vacumm chamber and dropping it out of an airplane. We currently have a usable frame – 5.5 inch outer diameter, 10 foot long, standard 98 mm motor mount, mostly aluminum with custom made fiberglass nose cone and aeroshell. We have made one successful flight (last year) on an N motor to ~12,000 ft. This was really less a formal flight and more a "one more time" recovery systems test. So now we have this rocket and we are getting back to filling it with electronics. We are moving our data bus from CAN to USB. The new IMU will have much much better gyros that could be obtained (for cheap) in 2005. We also have a new flight computer software. The current plan is to make several more launches this year, slowly adding custom electronics back in to the system.

Some people (before my time) were making a GOX/paraffin hybrid motor, but interest died out and no one has picked it back up.

Our big successes is the design and open sourcing of our cylindrical patch antennas. The only ones that we found at the time (2003) were meant for military application and coasted tens of thousands of dollars. We figured out how to do it cheaply ($100) and even tested them in an anechoic chamber. Plus they are flight tested.

We also have extensive experience with GPS. Several of our members are intimately familiar with the inner workings of GPS and have worked on the open source implementation of GPS hardware – GPL-GPS.

Our most important (we think) research is the flight computer/IMU. The motors and airframes are really not the hard part of space flight. Doing GNC is many orders of magnitude times harder than physically building a rocket and putting fuel in it. Not that the mechanical/propulsion systems aren't difficult, important or interesting, but we feel like there is a lot of really cool stuff to do on the software side.

So. Yes. Hi.

We have been hard at work under the radar for many years on a lot of the pieces of open source space flight and we are more than happy to share and collaborate. And like any other group in this niche right now we need funding. I think we have a lot in common, so lets talk!

-Nathan

Wow, I'm really excited about PSAS. Technically, we overlap a lot, it seems. I was thinking of abusing the engine nozzle as an antenna, but didn't get to simulate it yet, since I'm buried in other work. I didn't think about the cylindrical patch antenna though! I was also thinking about using CAN onboard. It's very interesting to me why you decided to use USB instead of CAN.

Anyways… Awesome to hear from you guys!

I envision this becoming a very important partnership for CSTART. It sounds like PSAS has some great experience with navigation and telemetry. OHKLA can serve as a platform for us to develop a more refined and versatile GNC system. I can also realistically see a two or three staged OHKLA derivative becoming the first amateur rocket to reach Earth orbit.

Hey

Sorry, I've been pretty busy the last couple of weeks. Among other
things I managed to break apt-get in a way such that after an update I
was left with an unbootable system. Fun times. The good news is it was
as good of chance as any to try out Ubuntu 10.4 beta. It's very nice
looking.

Anyway we (collectively) have been doing this rocket
thing for something like 12 years, so we think in terms of months, not
days. We don't think you've been "slow" about anything :) As far a joint
project I am curious what you have in mind?  We're more than happy to
share knowledge but we have very limited bandwidth to make things (we
can
barely get our own stuff built).

We don't actually
have any facilities as a group, what we have is some members who either
own or have access to facilities. So making this is a case by case
situation. We also get local companies to do pro bono work for
us
because we are an 'educational' group.  We have some group members that
are TRA level 2 citified, but no one (yet) level 3.  We always launch
under the umbrella of some event, in our case usually put on by Oregon
Rocketry (O-Rock).  Then we find a level 3 person to actually handle to
motors on the day of. A lot of us also have amateur radio licenses.
These are extremely easy to get in the US and allows us to do all of our
communication stuff.

As far as launching rockets this
is all we have officially in terms of certifications. You don't need a
whole lot in the US for small launches like this. The hard part
(legally) is handled by groups like TRA and O-Rock and all we do is show
up. This is assuming you're not making your own motors, which is a
whole other ball of string.  I think that hybrid motors are especially
nice in this regard because you can do it without any special
certifications because the materials by themselves are safe. Our
strategy right now is to continue launching with commercial motors. Some
day a large hybrid would be nice though.

ITAR is a huge pain in our sides.  We need some
serious international law expertise to be for sure for sure, but we are
convinced that ITAR applies to us regardless of our open source status.
This is actually something that worries many of us in the group,
especially when in comes to collaborations like this one.  There have
been several cases of people getting prosecuted under ITAR for letting
non US citizens have access (and on all accounts with pure intentions)
to "restricted" information. Luckily we shouldn't have anything yet that
is covered under ITAR but it covers a lot and we are close. There are
some things we will keep close to our chest until we get better legal
support.  In fact we need to double up our efforts to find someone who
can help us clear things up about exactly what we can and can't do.

Does that answer your questions?